The dry developing method is widely used to develop electrostatic charge images in electrophotography and such. In the dry developing method, toner which contains dispersed coloring agents such as carbon black is used.
Toner is a fine powder developing agent capable of frictional electrification. Toner is electrified by friction and, because of electrical attraction, adheres to electrostatic latent images on the photosensitive matter to form toner images. The toner images thus formed are then transferred onto paper and fixed with a heating roller(s).
Toner is required to have anti-offset properties (that is, the toner does not stick to the heating roller(s)), fixability (the toner adheres firmly to the paper), anti-blocking properties (the toner particles do not aggregate), etc. For the purpose of improving the anti-offset properties, toners containing toner resin compositions which were given a wider molecular weight distribution by using a low molecular weight component(s) and a high molecular weight component(s) were proposed in Japanese unexamined patent publication (Tokkai) Sho 50-134652, Tokkai Sho 56-16144 and Tokkai Sho 56-158340. However, the resin composition having a wide molecular weight distribution simply by using a low molecular weight component(s) and a high molecular weight component(s) does not quite acquire sufficient anti-offset properties.
The object of the present invention is to provide an improved toner resin composition and a toner containing same, wherein said toner resin composition is easy to manufacture, has improved anti-offset properties as well as superior anti-blocking properties and fixability, and also has stable electrification characteristics.